Optical lens assembly

ABSTRACT

An optical lens assembly includes an aperture stop, a first lens element to a sixth lens element from an object side toward an image side along an optical axis. The third lens element has an object-side surface with a concave portion in a vicinity of its periphery, and an image-side surface with a convex portion in a vicinity of the optical axis. The fourth lens element has an image-side surface with a convex portion in a vicinity of the optical axis. The fifth lens element positive refractive power has an object-side surface with a convex portion in a vicinity of the optical axis. The sixth lens element has an object-side surface with a convex portion in a vicinity of its periphery. The thickness of lens elements T 1 , T 2 , T 3 , T 4 , T 6  satisfies (T 1 +T 2 +T 3 +T 4 )/T 6 ≦4.0.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Chinese patent application No.201610003040.0, filed on Jan. 4, 2016, the contents of which are herebyincorporated by reference in their entirety for all purposes.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to an optical imaging lens set.Specifically speaking, the present invention is directed to a shorteroptical imaging lens set of six lens elements for use in mobile phones,in cameras, in tablet personal computers, in in-car cameras, or inpersonal digital assistants (PDA).

2. Description of the Prior Art

In recent years, the popularity of mobile phones and digital camerasmakes the sizes of various portable electronic products reduce quickly,and so does those of the photography modules. The current trend ofresearch is to develop an optical imaging lens set of a shorter lengthwith uncompromised good quality. With the development and shrinkage of acharge coupled device (CCD) or a complementary metal oxide semiconductorelement (CMOS), the optical imaging lens set installed in thephotography module shrinks as well to meet the demands. However, goodand necessary optical properties, such as the system aberrationimprovement, as well as production cost and production feasibilityshould be taken into consideration, too.

The specifications of portable electronic products develop quickly, sodoes the key component —the photography modules. In addition to takingpictures and doing video recording, they may be used to do environmentalsurveillance or to serve as dashboard cameras. The demand not only forbetter quality but also for dim light background, larger field of viewand smaller lens set space is getting higher and higher so there is aneed for a lens set of better image quality and smaller size.

The designing of the optical lens is not just scaling down the opticallens which has good optical performance, but also needs to consider thematerial characteristics and satisfy some practical requirements likeassembly yield. Therefore, how to reduce the total length of aphotographic device, but still maintain good optical performance underdim light background, is an important objective to research.

SUMMARY OF THE INVENTION

In light of the above, the present invention proposes an optical imaginglens set that is lightweight, has a low production cost, has an enlargedhalf of field of view, has a high resolution and has high image quality.The optical imaging lens set of six lens elements of the presentinvention from an object side toward an image side in order along anoptical axis has an aperture stop, a first lens element, a second lenselement, a third lens element, a fourth lens element, a fifth lenselement and a sixth lens element. Each lens element has an object-sidesurface facing toward an object side as well as an image-side surfacefacing toward an image side. The optical imaging lens set exclusivelyhas the first lens element, the second lens element, the third lenselement, the fourth lens element, the fifth lens element and the sixthlens element with refractive power.

In a first aspect, the first lens element has refractive power, and atleast one of its object-side surface as well as its image-side surfaceis an aspheric surface. The second lens element has refractive power, animage-side surface with a concave portion in a vicinity of its peripheryand at least one of its object-side surface as well as its image-sidesurface is an aspheric surface. The third lens element has anobject-side surface with a concave portion in a vicinity of itsperiphery and an image-side surface with a convex portion in a vicinityof the optical axis. The fourth lens element has an image-side surfacewith a convex portion in a vicinity of the optical axis and at least oneof its object-side surface as well as its image-side surface is anaspheric surface. The fifth lens element has positive refractive power,an object-side surface with a convex portion in a vicinity of theoptical axis, and both its object-side surface and its image-sidesurface are aspheric surfaces. The sixth lens element has an object-sidesurface with a convex portion in a vicinity of the optical axis and aconvex portion in a vicinity of its periphery and both its object-sidesurface and its image-side surface are aspheric surfaces. The first lenselement has a first lens element thickness T₁, the second lens elementhas a second lens element thickness T₂, the third lens element has athird lens element thickness T₃, the fourth lens element has a fourthlens element thickness T₄, the sixth lens element has a sixth lenselement thickness T₆ to satisfy (T₁+T₂+T₃+T₄)/T₆≦4.0.

The optical imaging lens set of sixth lens elements of the presentinvention further satisfies (T₃+T₆)/T₁≦1.9.

In the optical imaging lens set of sixth lens elements of the presentinvention, the fifth lens element has a fifth lens element thickness T₅to satisfy (T₃+T₆)/T₅≦2.1.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfies (T₃+T₆)/G₁₂≦8.0.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₃₄ between the third lens element and the fourthlens element along the optical axis satisfies (T₃+T₆)/G₃₄≦2.8.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₅₆ between the fifth lens element and the sixthlens element along the optical axis satisfies (T₃+T₆)/G₅₆≦3.3.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₁₂ between the first lens element and the secondlens element along the optical axis and an air gap G₂₃ between thesecond lens element and the third lens element along the optical axissatisfy (T₃+T₆)/(G₁₂+G₂₃)≦1.8.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₂₃ between the second lens element and the thirdlens element along the optical axis and an air gap G₅₆ between the fifthlens element and the sixth lens element along the optical axis satisfy(T₃+T₆)/(G₂₃+G₅₆)≦1.4.

The optical imaging lens set of sixth lens elements of the presentinvention satisfies (T₃+T₆)/T₂≦3.8.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfies (T₄+T₆)/G₁₂≦5.5.

In a second aspect, the first lens element has refractive power, and atleast one of its object-side surface as well as its image-side surfaceis an aspheric surface. The second lens element has refractive power, animage-side surface with a concave portion in a vicinity of its peripheryand at least one of its object-side surface as well as its image-sidesurface is an aspheric surface. The third lens element has anobject-side surface with a concave portion in a vicinity of itsperiphery and an image-side surface with a convex portion in a vicinityof the optical axis. The fourth lens element has an image-side surfacewith a convex portion in a vicinity of the optical axis and at least oneof its object-side surface as well as its image-side surface is anaspheric surface. The fifth lens element has positive refractive power,an object-side surface with a convex portion in a vicinity of theoptical axis, an image-side surface with a concave portion in a vicinityof the optical axis and both its object-side surface and its image-sidesurface are aspheric surfaces. The sixth lens element has an object-sidesurface with a convex portion in a vicinity of its periphery and bothits object-side surface and its image-side surface are asphericsurfaces. The first lens element has a first lens element thickness T₁,the second lens element has a second lens element thickness T₂, thethird lens element has a third lens element thickness T₃, the fourthlens element has a fourth lens element thickness T₄, the sixth lenselement has a sixth lens element thickness T₆ to satisfy(T₁+T₂+T₃+T₄)/T₆≦4.0.

The optical imaging lens set of sixth lens elements of the presentinvention further satisfies (T₃+T₆)/T₁≦1.9.

In the optical imaging lens set of sixth lens elements of the presentinvention, the fifth lens element has a fifth lens element thickness T₅to satisfy (T₃+T₆)/T₅≦2.1.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₂₃ between the second lens element and the thirdlens element along the optical axis satisfies (T₄+T₆)/G₂₃≦1.8.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₃₄ between the third lens element and the fourthlens element along the optical axis satisfies (T₄+T₆)/G₃₄≦1.8.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₂₃ between the fifth lens element and the sixthlens element along the optical axis satisfies (T₄+T₆)/G₅₅≦2.5.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfies T₃/G₁₂≦2.9.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfies T₄/G₁₂≦2.6.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₁₂ between the first lens element and the secondlens element along the optical axis and the fifth lens element with afifth lens element thickness T₅ satisfy T₅/G₁₂≦3.6.

In the optical imaging lens set of sixth lens elements of the presentinvention, an air gap G₁₂ between the first lens element and the secondlens element along the optical axis satisfies T₆/G₁₂≦2.7.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 illustrates the methods for determining the surface shapes andfor determining one region is a region in a vicinity of the optical axisor the region in a vicinity of its circular periphery of one lenselement.

FIG. 6 illustrates a first example of the optical imaging lens set ofthe present invention.

FIG. 7A illustrates the longitudinal spherical aberration on the imageplane of the first example.

FIG. 7B illustrates the astigmatic aberration on the sagittal directionof the first example.

FIG. 7C illustrates the astigmatic aberration on the tangentialdirection of the first example.

FIG. 7D illustrates the distortion aberration of the first example.

FIG. 8 illustrates a second example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 9A illustrates the longitudinal spherical aberration on the imageplane of the second example.

FIG. 9B illustrates the astigmatic aberration on the sagittal directionof the second example.

FIG. 9C illustrates the astigmatic aberration on the tangentialdirection of the second example.

FIG. 9D illustrates the distortion aberration of the second example.

FIG. 10 illustrates a third example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 11A illustrates the longitudinal spherical aberration on the imageplane of the third example.

FIG. 11B illustrates the astigmatic aberration on the sagittal directionof the third example.

FIG. 11C illustrates the astigmatic aberration on the tangentialdirection of the third example.

FIG. 11D illustrates the distortion aberration of the third example.

FIG. 12 illustrates a fourth example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 13A illustrates the longitudinal spherical aberration on the imageplane of the fourth example.

FIG. 13B illustrates the astigmatic aberration on the sagittal directionof the fourth example.

FIG. 13C illustrates the astigmatic aberration on the tangentialdirection of the fourth example.

FIG. 13D illustrates the distortion aberration of the fourth example.

FIG. 14 illustrates a fifth example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 15A illustrates the longitudinal spherical aberration on the imageplane of the fifth example.

FIG. 15B illustrates the astigmatic aberration on the sagittal directionof the fifth example.

FIG. 15C illustrates the astigmatic aberration on the tangentialdirection of the fifth example.

FIG. 15D illustrates the distortion aberration of the fifth example.

FIG. 16 illustrates a sixth example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 17A illustrates the longitudinal spherical aberration on the imageplane of the sixth example.

FIG. 17B illustrates the astigmatic aberration on the sagittal directionof the sixth example.

FIG. 17C illustrates the astigmatic aberration on the tangentialdirection of the sixth example.

FIG. 17D illustrates the distortion aberration of the sixth example.

FIG. 18 illustrates a seventh example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 19A illustrates the longitudinal spherical aberration on the imageplane of the seventh example.

FIG. 19B illustrates the astigmatic aberration on the sagittal directionof the seventh example.

FIG. 19C illustrates the astigmatic aberration on the tangentialdirection of the seventh example.

FIG. 19D illustrates the distortion aberration of the seventh example.

FIG. 20 illustrates an eighth example of the optical imaging lens set ofsix lens elements of the present invention.

FIG. 21A illustrates the longitudinal spherical aberration on the imageplane of the eighth example.

FIG. 21B illustrates the astigmatic aberration on the sagittal directionof the eighth example.

FIG. 21C illustrates the astigmatic aberration on the tangentialdirection of the eighth example.

FIG. 21D illustrates the distortion aberration of the eighth example.

FIG. 22 illustrates a first preferred example of the portable electronicdevice with an optical imaging lens set of the present invention.

FIG. 23 illustrates a second preferred example of the portableelectronic device with an optical imaging lens set of the presentinvention.

FIG. 24 shows the optical data of the first example of the opticalimaging lens set.

FIG. 25 shows the aspheric surface data of the first example.

FIG. 26 shows the optical data of the second example of the opticalimaging lens set.

FIG. 27 shows the aspheric surface data of the second example.

FIG. 28 shows the optical data of the third example of the opticalimaging lens set.

FIG. 29 shows the aspheric surface data of the third example.

FIG. 30 shows the optical data of the fourth example of the opticalimaging lens set.

FIG. 31 shows the aspheric surface data of the fourth example.

FIG. 32 shows the optical data of the fifth example of the opticalimaging lens set.

FIG. 33 shows the aspheric surface data of the fifth example.

FIG. 34 shows the optical data of the sixth example of the opticalimaging lens set.

FIG. 35 shows the aspheric surface data of the sixth example.

FIG. 36 shows the optical data of the seventh example of the opticalimaging lens set.

FIG. 37 shows the aspheric surface data of the seventh example.

FIG. 38 shows the optical data of the eighth example of the opticalimaging lens set.

FIG. 39 shows the aspheric surface data of the eighth example.

FIG. 40 shows some important ratios in the examples.

DETAILED DESCRIPTION

Before the detailed description of the present invention, the firstthing to be noticed is that in the present invention, similar (notnecessarily identical) elements are labeled as the same numeralreferences. In the entire present specification, “a certain lens elementhas negative/positive refractive power” refers to the part in a vicinityof the optical axis of the lens element has negative/positive refractivepower calculated by Gaussian optical theory. An object-side/image-sidesurface refers to the region which allows imaging light passing through,in the drawing, imaging light includes Lc (chief ray) and Lm (marginalray). As shown in FIG. 1, the optical axis is “I” and the lens elementis symmetrical with respect to the optical axis I. The region A thatnear the optical axis and for light to pass through is the region in avicinity of the optical axis, and the region C that the marginal raypassing through is the region in a vicinity of a certain lens element'scircular periphery. In addition, the lens element may include anextension part E for the lens element to be installed in an opticalimaging lens set (that is the region outside the region C perpendicularto the optical axis). Ideally speaking, no light would pass through theextension part, and the actual structure and shape of the extension partis not limited to this and may have other variations. For the reason ofsimplicity, the extension part is not illustrated in the followingexamples. More, precisely, the method for determining the surface shapesor the region in a vicinity of the optical axis, the region in avicinity of its circular periphery and other regions is described in thefollowing paragraphs:

1. FIG. 1 is a radial cross-sectional view of a lens element. Beforedetermining boundaries of those aforesaid portions, two referentialpoints should be defined first, middle point and conversion point. Themiddle point of a surface of a lens element is a point of intersectionof that surface and the optical axis. The conversion point is a point ona surface of a lens element, where the tangent line of that point isperpendicular to the optical axis. Additionally, if multiple conversionpoints appear on one single surface, then these conversion points aresequentially named along the radial direction of the surface withnumbers starting from the first conversion point. For instance, thefirst conversion point (closest one to the optical axis), the secondconversion point, and the N^(th) conversion point (farthest one to theoptical axis within the scope of the clear aperture of the surface). Theportion of a surface of the lens element between the middle point andthe first conversion point is defined as the portion in a vicinity ofthe optical axis. The portion located radially outside of the N^(th)conversion point (but still within the scope of the clear aperture) isdefined as the portion in a vicinity of a periphery of the lens element.In some embodiments, there are other portions existing between theportion in a vicinity of the optical axis and the portion in a vicinityof a periphery of the lens element; the numbers of portions depend onthe numbers of the conversion point(s). In addition, the radius of theclear aperture (or a so-called effective radius) of a surface is definedas the radial distance from the optical axis I to a point ofintersection of the marginal ray Lm and the surface of the lens element.2. Referring to FIG. 2, determining the shape of a portion is convex orconcave depends on whether a collimated ray passing through that portionconverges or diverges. That is, while applying a collimated ray to aportion to be determined in terms of shape, the collimated ray passingthrough that portion will be bended and the ray itself or its extensionline will eventually meet the optical axis. The shape of that portioncan be determined by whether the ray or its extension line meets(intersects) the optical axis (focal point) at the object-side orimage-side. For instance, if the ray itself intersects the optical axisat the image side of the lens element after passing through a portion,i.e. the focal point of this ray is at the image side (see point R inFIG. 2), the portion will be determined as having a convex shape. On thecontrary, if the ray diverges after passing through a portion, theextension line of the ray intersects the optical axis at the object sideof the lens element, i.e. the focal point of the ray is at the objectside (see point M in FIG. 2), that portion will be determined as havinga concave shape. Therefore, referring to FIG. 2, the portion between themiddle point and the first conversion point has a convex shape, theportion located radially outside of the first conversion point has aconcave shape, and the first conversion point is the point where theportion having a convex shape changes to the portion having a concaveshape, namely the border of two adjacent portions. Alternatively, thereis another common way for a person with ordinary skill in the art totell whether a portion in a vicinity of the optical axis has a convex orconcave shape by referring to the sign of an “R” value, which is the(paraxial) radius of curvature of a lens surface. The R value iscommonly used in conventional optical design software such as Zemax andCodeV. The R value usually appears in the lens data sheet in thesoftware. For an object-side surface, positive R means that theobject-side surface is convex, and negative R means that the object-sidesurface is concave. Conversely, for an image-side surface, positive Rmeans that the image-side surface is concave, and negative R means thatthe image-side surface is convex. The result found by using this methodshould be consistent as by using the other way mentioned above, whichdetermines surface shapes by referring to whether the focal point of acollimated ray is at the object side or the image side.3. For none conversion point cases, the portion in a vicinity of theoptical axis is defined as the portion between 0˜50% of the effectiveradius (radius of the clear aperture) of the surface, whereas theportion in a vicinity of a periphery of the lens element is defined asthe portion between 50˜100% of effective radius (radius of the clearaperture) of the surface.

Referring to the first example depicted in FIG. 3, only one conversionpoint, namely a first conversion point, appears within the clearaperture of the image-side surface of the lens element. Portion I is aportion in a vicinity of the optical axis, and portion II is a portionin a vicinity of a periphery of the lens element. The portion in avicinity of the optical axis is determined as having a concave surfacedue to the R value at the image-side surface of the lens element ispositive. The shape of the portion in a vicinity of a periphery of thelens element is different from that of the radially inner adjacentportion, i.e. the shape of the portion in a vicinity of a periphery ofthe lens element is different from the shape of the portion in avicinity of the optical axis; the portion in a vicinity of a peripheryof the lens element has a convex shape.

Referring to the second example depicted in FIG. 4, a first conversionpoint and a second conversion point exist on the object-side surface(within the clear aperture) of a lens element. In which portion I is theportion in a vicinity of the optical axis, and portion III is theportion in a vicinity of a periphery of the lens element. The portion ina vicinity of the optical axis has a convex shape because the R value atthe object-side surface of the lens element is positive. The portion ina vicinity of a periphery of the lens element (portion III) has a convexshape. What is more, there is another portion having a concave shapeexisting between the first and second conversion point (portion II).

Referring to a third example depicted in FIG. 5, no conversion pointexists on the object-side surface of the lens element. In this case, theportion between 0˜50% of the effective radius (radius of the clearaperture) is determined as the portion in a vicinity of the opticalaxis, and the portion between 50˜100% of the effective radius isdetermined as the portion in a vicinity of a periphery of the lenselement. The portion in a vicinity of the optical axis of theobject-side surface of the lens element is determined as having a convexshape due to its positive R value, and the portion in a vicinity of aperiphery of the lens element is determined as having a convex shape aswell.

As shown in FIG. 6, the optical imaging lens set 1 of six lens elementsof the present invention, sequentially located from an object side 2(where an object is located) to an image side 3 along an optical axis 4,has an aperture stop (ape. stop) 80, a first lens element 10, a secondlens element 20, a third lens element 30, a fourth lens element 40, afifth lens element 50, a sixth lens element 60, a filter 70 and an imageplane 71. Generally speaking, the first lens element 10, the second lenselement 20, the third lens element 30, the fourth lens element 40, thefifth lens element 50 and the sixth lens element 60 may be made of atransparent plastic material but the present invention is not limited tothis and each has an appropriate refractive power. There are exclusivelysix lens elements, which means the first lens element 10, the secondlens element 20, the third lens element 30, the fourth lens element 40,the fifth lens element 50 and the sixth lens element 60, with refractivepower in the optical imaging lens set 1 of the present invention. Theoptical axis 4 is the optical axis of the entire optical imaging lensset 1, and the optical axis of each of the lens elements coincides withthe optical axis of the optical imaging lens set 1.

Furthermore, the optical imaging lens set 1 includes an aperture stop(ape. stop) 80 disposed in an appropriate position. In FIG. 6, theaperture stop 80 is disposed between the object side 2 and the firstlens element 10. When light emitted or reflected by an object (notshown) which is located at the object side 2 enters the optical imaginglens set 1 of the present invention, it forms a clear and sharp image onthe image plane 71 at the image side 3 after passing through theaperture stop 80, the first lens element 10, the second lens element 20,the third lens element 30, the fourth lens element 40, the fifth lenselement 50, the sixth lens element 60 and the filter 70. In oneembodiments of the present invention, the optional filter 70 may be afilter of various suitable functions, for example, the filter 70 may bean infrared cut filter (IR cut filter), placed between the image-sidesurface 62 of the sixth lens element 60 and the image plane 71.

Each lens element in the optical imaging lens set 1 of the presentinvention has an object-side surface facing toward the object side 2 aswell as an image-side surface facing toward the image side 3. Forexample, the first lens element 10 has a first object-side surface 11and a first image-side surface 12; the second lens element 20 has asecond object-side surface 21 and a second image-side surface 22; thethird lens element 30 has a third object-side surface 31 and a thirdimage-side surface 32; the fourth lens element 40 has a fourthobject-side surface 41 and a fourth image-side surface 42; the fifthlens element 50 has a fifth object-side surface 51 and a fifthimage-side surface 52; the sixth lens element 60 has a sixth object-sidesurface 61 and a sixth image-side surface 62. In addition, eachobject-side surface and image-side surface in the optical imaging lensset 1 of the present invention has a part (or portion) in a vicinity ofits circular periphery (circular periphery part) away from the opticalaxis 4 as well as a part in a vicinity of the optical axis (optical axispart) close to the optical axis 4.

Each lens element in the optical imaging lens set 1 of the presentinvention further has a central thickness T on the optical axis 4. Forexample, the first lens element 10 has a first lens element thicknessT₁, the second lens element 20 has a second lens element thickness T₂,the third lens element 30 has a third lens element thickness T₃, thefourth lens element 40 has a fourth lens element thickness T₄, the fifthlens element 50 has a fifth lens element thickness T₅, the sixth lenselement 60 has a sixth lens element thickness T₆. Therefore, the totalthickness of all the lens elements in the optical imaging lens set 1along the optical axis 4 is ALT=T₁+T₂+T₃+T₄+T₅+T₆.

In addition, between two adjacent lens elements in the optical imaginglens set 1 of the present invention there is an air gap along theoptical axis 4. For example, an air gap G₁₂ is disposed between thefirst lens element 10 and the second lens element 20, an air gap G₂₃ isdisposed between the second lens element 20 and the third lens element30, an air gap G₃₄ is disposed between the third lens element 30 and thefourth lens element 40, an air gap G₄₅ is disposed between the fourthlens element 40 and the fifth lens element 50 as well as an air gap G₅₆is disposed between the fifth lens element 50 and the sixth lens element60. Therefore, the sum of total five air gaps between adjacent lenselements from the first lens element 10 to the sixth lens element 60along the optical axis 4 is AAG=G₁₂+G₂₃+G₃₄+G₄₅+G₅₆.

In addition, the distance between the first object-side surface 11 ofthe first lens element 10 to the image plane 71, namely the total lengthof the optical imaging lens set along the optical axis 4 is TTL; theeffective focal length of the optical imaging lens set is EFL; thedistance between the sixth image-side surface 62 of the sixth lenselement 60 to the image plane 71 along the optical axis 4 is BFL.

Furthermore, the focal length of the first lens element 10 is f1; thefocal length of the second lens element 20 is f2; the focal length ofthe third lens element 30 is f3; the focal length of the fourth lenselement 40 is f4; the focal length of the fifth lens element 50 is f5;the focal length of the sixth lens element 60 is f6; the refractiveindex of the first lens element 10 is n1; the refractive index of thesecond lens element 20 is n2; the refractive index of the third lenselement 30 is n3; the refractive index of the fourth lens element 40 isn4; the refractive index of the fifth lens element 50 is n5; therefractive index of the sixth lens element 60 is n6; the Abbe number ofthe first lens element 10 is ν1; the Abbe number of the second lenselement 20 is ν2; the Abbe number of the third lens element 30 is ν3;and the Abbe number of the fourth lens element 40 is ν4; the Abbe numberof the fifth lens element 50 is ν5; and the Abbe number of the sixthlens element 60 is ν6.

First Example

Please refer to FIG. 6 which illustrates the first example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 7A for the longitudinal spherical aberration on the image plane 71of the first example; please refer to FIG. 7B for the astigmatic fieldaberration on the sagittal direction; please refer to FIG. 7C for theastigmatic field aberration on the tangential direction, and pleaserefer to FIG. 7D for the distortion aberration. The Y axis of thespherical aberration in each example is “field of view” for 1.0. The Yaxis of the astigmatic field and the distortion in each example standsfor “image height”, which is 3.413 mm.

The optical imaging lens set 1 of the first example has six lenselements 10 to 60 with refractive power. The optical imaging lens set 1also has a filter 70, an aperture stop 80, and an image plane 71. Theaperture stop 80 is provided between the object side 2 and the firstlens element 10. The filter 70 may be used for preventing specificwavelength light (such as the infrared light) reaching the image planeto adversely affect the imaging quality.

The first lens element 10 has positive refractive power. The firstobject-side surface 11 facing toward the object side 2 has a convex part13 in the vicinity of the optical axis and a convex part 14 in avicinity of its circular periphery. The first image-side surface 12facing toward the image side 3 has a concave part 16 in the vicinity ofthe optical axis and a convex part 17 in a vicinity of its circularperiphery. Besides, at least one of the first object-side surface 11 andthe first image-side 12 of the first lens element 10 is aspherical.

The second lens element 20 has negative refractive power. The secondobject-side concave surface 21 facing toward the object side 2 has aconvex part 23 in the vicinity of the optical axis and a concave part 24in a vicinity of its circular periphery. The second image-side surface22 facing toward the image side 3 has a concave part 26 in the vicinityof the optical axis and a concave part 27 in a vicinity of its circularperiphery. At least one of the second object-side surface 21 and thesecond image-side 22 of the second lens element 20 is aspherical.

The third lens element 30 has positive refractive power. The thirdobject-side surface 31 facing toward the object side 2 has a convex part33 in the vicinity of the optical axis and a concave part 34 in avicinity of its circular periphery. The third image-side surface 32facing toward the image side 3 has a convex part 36 in the vicinity ofthe optical axis and a convex part 37 in a vicinity of its circularperiphery. At least one of the third object-side surface 31 and thethird image-side 32 of the third lens element 30 is aspherical.

The fourth lens element 40 has negative refractive power. The fourthobject-side surface 41 facing toward the object side 2 has a concavepart 43 in the vicinity of the optical axis and a concave part 44 in avicinity of its circular periphery. The fourth image-side surface 42facing toward the image side 3 has a convex part 46 in the vicinity ofthe optical axis and a convex part 47 in a vicinity of its circularperiphery. At least one of the fourth object-side surface 41 and thefourth image-side 42 of the fourth lens element 40 is aspherical.

The fifth lens element 50 has positive refractive power. The fifthobject-side surface 51 facing toward the object side 2 has a convex part53 in the vicinity of the optical axis and a concave part 54 in avicinity of its circular periphery. The fifth image-side surface 52facing toward the image side 3 has a concave part 56 in the vicinity ofthe optical axis and a convex part 57 in a vicinity of its circularperiphery. Both the fifth object-side surface 51 and the fifthimage-side 52 of the fifth lens element 50 are aspherical surfaces.

The sixth lens element 60 has negative refractive power. The sixthobject-side surface 61 facing toward the object side 2 has a convex part63 in the vicinity of the optical axis and a convex part 64 in avicinity of its circular periphery. The sixth image-side surface 62facing toward the image side 3 has a concave part 66 in the vicinity ofthe optical axis and a convex part 67 in a vicinity of its circularperiphery. Both the sixth object-side surface 61 and the sixthimage-side 62 of the sixth lens element 60 are aspherical surfaces. Thefilter 70 may be disposed between the sixth image-side 62 of the sixthlens element 60 and the image plane 71.

In the first lens element 10, the second lens element 20, the third lenselement 30, the fourth lens element 40, the fifth lens element 50 andthe sixth lens element 60 of the optical imaging lens element 1 of thepresent invention, there are 12 surfaces, such as the object-sidesurfaces 11/21/31/41/51/61 and the image-side surfaces12/22/32/42/52/62. If a surface is aspherical, these asphericcoefficients are defined according to the following formula:

${Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}\; {a_{i} \times Y^{i}}}}$

In which:R represents the curvature radius of the lens element surface;Z represents the depth of an aspherical surface (the perpendiculardistance between the point of the aspherical surface at a distance Yfrom the optical axis and the tangent plane of the vertex on the opticalaxis of the aspherical surface);Y represents a vertical distance from a point on the aspherical surfaceto the optical axis;K is a conic constant;a_(i) is the aspheric coefficient of the i^(th) order.

The optical data of the first example of the optical imaging lens set 1are shown in FIG. 24 while the aspheric surface data are shown in FIG.25. In the present examples of the optical imaging lens set, thef-number of the entire optical lens element system is Fno, EFL is theeffective focal length, HFOV stands for the half field of view which ishalf of the field of view of the entire optical lens element system, andthe unit for the curvature radius, the thickness and the focal length isin millimeters (mm). Fno is 2.0497. The image height is 3.413 mm. HFOVis 37.4916 degrees.

The TTL of the first example of the present invention is effectivelyreduced and the chromatic aberration is decreased to provide betterimaging quality. The demonstrated first example may maintain a goodoptical performance and reduced lens set length to realize a smallerproduct design.

Second Example

Please refer to FIG. 8 which illustrates the second example of theoptical imaging lens set 1 of the present invention. It is noted thatfrom the second example to the following examples, in order to simplifythe figures, only the components different from what the first examplehas, and the basic lens elements will be labeled in figures. Othercomponents that are the same as what the first example has, such as theobject-side surface, the image-side surface, the part in a vicinity ofthe optical axis and the part in a vicinity of its circular peripherywill be omitted in the following examples. Please refer to FIG. 9A forthe longitudinal spherical aberration on the image plane 71 of thesecond example, please refer to FIG. 9B for the astigmatic aberration onthe sagittal direction, please refer to FIG. 9C for the astigmaticaberration on the tangential direction, and please refer to FIG. 9D forthe distortion aberration. The components in the second example aresimilar to those in the first example, but the optical data such as thecurvature radius, the refractive power, the lens thickness, the lensfocal length, the aspheric surface or the back focal length in thisexample are different from the optical data in the first example. Inparticular, 1) the TTL of the second example is shorter than that of thefirst example of the present invention. 2) The second example is easierto be fabricated so the yield would be better.

The optical data of the second example of the optical imaging lens setare shown in FIG. 26 while the aspheric surface data are shown in FIG.27. The image height is 3.413 mm. Fno is 2.0497. HFOV is 37.4916degrees.

Third Example

Please refer to FIG. 10 which illustrates the third example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 11A for the longitudinal spherical aberration on the image plane 71of the third example; please refer to FIG. 11B for the astigmaticaberration on the sagittal direction; please refer to FIG. 11C for theastigmatic aberration on the tangential direction, and please refer toFIG. 11D for the distortion aberration. The components in the thirdexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the first image-side surface 12 of the first lenselement 10 has a concave part 17′ in a vicinity of its circularperiphery. In particular, 1) the TTL of the third example is shorterthan that of the first example of the present invention. 2) The imagingquality of the third example is better than the first example. 3) Thethird example is easier to be fabricated than the first example so theyield would be better.

The optical data of the third example of the optical imaging lens setare shown in FIG. 28 while the aspheric surface data are shown in FIG.29. The image height is 3.413 mm. Fno is 2.0497. HFOV is 37.4916degrees.

Fourth Example

Please refer to FIG. 12 which illustrates the fourth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 13A for the longitudinal spherical aberration on the image plane 71of the fourth example; please refer to FIG. 13B for the astigmaticaberration on the sagittal direction; please refer to FIG. 13C for theastigmatic aberration on the tangential direction, and please refer toFIG. 13D for the distortion aberration. The components in the fourthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the first image-side surface 12 of the first lenselement 10 has a concave part 17′ in a vicinity of its circularperiphery. In particular, the fourth example is easier to be fabricatedthan the first example so the yield would be better.

The optical data of the fourth example of the optical imaging lens setare shown in FIG. 30 while the aspheric surface data are shown in FIG.31. The image height is 3.413 mm. Fno is 2.0497. HFOV is 37.4916degrees.

Fifth Example

Please refer to FIG. 14 which illustrates the fifth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 15A for the longitudinal spherical aberration on the image plane 71of the fifth example; please refer to FIG. 15B for the astigmaticaberration on the sagittal direction; please refer to FIG. 15C for theastigmatic aberration on the tangential direction, and please refer toFIG. 15D for the distortion aberration. The components in the fifthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example.In particular, 1) the TTL of the fifth example is shorter than that ofthe first example of the present invention. 2) The imaging quality ofthe fifth example is better than the first example. 3) The fifth exampleis easier to be fabricated than the first example so the yield would bebetter.

The optical data of the fifth example of the optical imaging lens setare shown in FIG. 32 while the aspheric surface data are shown in FIG.33. The image height is 3.413 mm. Fno is 2.0497. HFOV is 37.4916degrees.

Sixth Example

Please refer to FIG. 16 which illustrates the sixth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 17A for the longitudinal spherical aberration on the image plane 71of the sixth example; please refer to FIG. 17B for the astigmaticaberration on the sagittal direction; please refer to FIG. 17C for theastigmatic aberration on the tangential direction, and please refer toFIG. 17D for the distortion aberration. The components in the sixthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the first image-side surface 12 of the first lenselement 10 has a concave part 17′ in a vicinity of its circularperiphery. In particular, the sixth example is easier to be fabricatedthan the first example so the yield would be better.

The optical data of the sixth example of the optical imaging lens setare shown in FIG. 34 while the aspheric surface data are shown in FIG.35. The image height is 3.413 mm. Fno is 2.0497. HFOV is 37.4916degrees.

Seventh Example

Please refer to FIG. 18 which illustrates the seventh example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 19A for the longitudinal spherical aberration on the image plane 71of the seventh example; please refer to FIG. 19B for the astigmaticaberration on the sagittal direction; please refer to FIG. 19C for theastigmatic aberration on the tangential direction, and please refer toFIG. 19D for the distortion aberration. The components in the seventhexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example.In particular, 1) the imaging quality of the seventh example is betterthan the first example, and 2) the seventh example is easier to befabricated than the first example so the yield would be better.

The optical data of the seventh example of the optical imaging lens setare shown in FIG. 36 while the aspheric surface data are shown in FIG.37. The image height is 3.413 mm. Fno is 2.0497. HFOV is 37.4916degrees.

Eighth Example

Please refer to FIG. 20 which illustrates the eighth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 21A for the longitudinal spherical aberration on the image plane 71of the eighth example; please refer to FIG. 21B for the astigmaticaberration on the sagittal direction; please refer to FIG. 21C for theastigmatic aberration on the tangential direction, and please refer toFIG. 21D for the distortion aberration. The components in the eighthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the first image-side surface 12 of the first lenselement 10 has a concave part 17′ in a vicinity of its circularperiphery. In particular, the eighth example is easier to be fabricatedthan the first example so the yield would be better.

The optical data of the eighth example of the optical imaging lens setare shown in FIG. 38 while the aspheric surface data are shown in FIG.39. The image height is 3.413 mm. Fno is 2.0497. HFOV is 37.4916degrees.

Some important ratios in each example are shown in FIG. 40. The distancebetween the sixth image-side surface 62 of the sixth lens element 60 tothe filter 70 along the optical axis 4 is G6F; the thickness of thefilter 70 along the optical axis 4 is TF; the distance between thefilter 70 to the image plane 71 along the optical axis 4 is GFP; thedistance between the sixth image-side surface 62 of the sixth lenselement 60 to the image plane 71 along the optical axis 4 is BFL.Therefore, BFL=G6F+TF+GFP.

In the light of the above examples, the inventors observe at least thefollowing features:

1. The first lens element with the refractive power along with thesecond image-side surface with a concave part in a vicinity of itscircular periphery helps correct the aberration of the first lenselement more easily. The third object-side surface with a convex part inthe vicinity of the optical axis and a concave part in a vicinity of itscircular periphery along with the fourth image-side surface with aconvex part in the vicinity of the optical axis help correct theaberration of the two previous lens elements. The positive refractivepower of the fifth lens element with the fifth object-side surface of aconvex part in the vicinity of the optical axis and the fifth image-sidesurface with a concave part in the vicinity of the optical axis helpsadjust the aberration of the four previous lens elements. The sixthobject-side surface with a convex part in the vicinity of the opticalaxis and with a convex part in a vicinity of its circular peripheryhelps correct the aberration of the five previous lens elements.2. At least one of the aspheric object-side surface as well as theaspheric image-side surface from the first lens element to the fourthlens element helps correct the collective comatic aberration,astigmatism, field curvature, distortion and off-axis chromaticaberration of the optical imaging lens set. The aspheric object-sidesurface as well as the aspheric image-side surface of both the fifthlens element and the sixth lens element helps correct the main comaticaberration, astigmatism, field curvature, distortion and off-axischromatic aberration. The parameters such as lens shape, lens thicknessand air gap involve the positioning of the aperture stop and theparameters depend on the optical features and length of the opticalimaging lens set. For example, the refractive power of the first lenselement effectively increases the positive refractive power of theoptical imaging lens set. It goes with the aperture stop positioned infront of the first object-side surface to increase the aperture stopavailable and to lower the F number so the positioning of the aperturestop is significant.

In addition, the inventors discover that there are some better ratioranges for different data according to the above various importantratios. Better ratio ranges help the designers to design a betteroptical performance and an effectively reduce length of a practicallypossible optical imaging lens set. For example: 1. The ratio of(T₁+T₂+T₃+T₄)/T₆≦4.0 helps increase the thickness of the sixth lenselement to facilitate the correction of the aberration of the fourprevious lens elements and to restrict the thickness of the sixth lenselement without being too small in order to increase the yield.Preferably, the ratio of 2.6≦(T₁+T₂+T₃+T₄)/T₆≦4.0 makes the thickness ofthe previous four lens element not so small to lower the yield or thethickness of the sixth lens element so great to increase the TTL.

2. The ratio of (T₃+T₆)/T₁≦1.9 is suggested to increase the thickness ofthe first lens element so that the thickness is not too small and ithelps the light meet at a point after passing through the aperture stop.Preferably, the ratio of 0.8≦(T₃+T₆)/T₁≦1.9 makes the thickness of thethird and sixth lens element not so small to lower the yield or thethickness of the first lens element so great to increase the TTL.3. The ratio of (T₃+T₆)/T₅≦2.1 is suggested to increase the thickness ofthe fifth lens element so that the thickness is not too small and ithelps correct the aberration of the previous four lens elements.Preferably, the ratio of 0.8≦(T₃+T₆)/T₅≦2.1 makes the thickness of thethird and sixth lens element not so small to lower the yield or thethickness of the fifth lens element so great to increase the TTL.4. The ratio of (T₃+T₆)/T₂≦3.8 is suggested to make the thickness of thesecond lens element not so small in order to increase the yield.Preferably, the ratio of 2.3≦(T₃+T₆)/T₂≦3.8 makes the thickness of thethird and sixth lens element not so small to lower the yield or thethickness of the second lens element so great to decrease the negativerefractive power.5. The ratio parameters of (T₃+T₆)/G₁₂≦8.0, (T₃+T₆)/G₃₄≦2.8,(T₃+T₆)/G₅₆≦3.3, (T₃+T₆)/(G₁₂+G₂₃)≦1.8, (T₃+T₆)/(G₂₃+G₅₆)≦1.4,(T₄+T₆)/G₁₂≦5.5, (T₄+T₆)/G₂₃≦1.8, (T₄+T₆)/G₃₄≦1.8, (T₄+T₆)/G₅₆≦2.5,T₃/G₁₂≦2.9, T₄/G₁₂≦2.6, T₅/G₁₂≦3.6, and T₆/G₁₂≦2.7, they are preferably3.0≦(T₃+T₆)/G₁₂≦8.0, 1.6≦(T₃+T₆)/G₃₄≦2.8, 1.8≦(T₃+T₆)/G₅₆≦3.3,0.9≦(T₃+T₆)/(G₁₂+G₂₃)≦1.8, 0.7≦(T₃+T₆)/(G₂₃+G₅₆)≦1.4,1.2≦(T₄+T₆)/G₁₂≦5.5, 1.0≦(T₄+T₆)/G₂₃≦1.8, 0.6≦(T₄+T₆)/G₃₄≦1.8,1.15≦(T₄+T₆)/G₅₆≦2.5, 2.35≦T₃/G₁₂≦2.9, 0.5≦T₄/G₁₂≦2.6, 1.7≦T₅/G₁₂≦3.6,and 0.6≦T₆/G₁₂≦2.7 in order to keep each thickness and each air gapwithin a proper range so that any parameter is not so great tocompromise the TTL. Or alternatively, any parameter is not so small tocompromise the assembly of the optical imaging lens set.

In the light of the unpredictability of the optical imaging lens set,the present invention suggests the above principles. The accordance ofthe principles preferably helps decrease the TTL, increase the aperturestop available, increase the HFOV, increase the imaging quality andincrease the yield of the assembling to overcome the drawbacks of priorart. The above limitations may be properly combined at the discretion ofpersons who practice the present invention and they are not limited asshown above.

The optical imaging lens set 1 of the present invention may be appliedto an electronic device, such as mobile phones or driving recorders.Please refer to FIG. 22. FIG. 22 illustrates a first preferred exampleof the optical imaging lens set 1 of the present invention for use in aportable electronic device 100. The electronic device 100 includes acase 110, and an image module 120 mounted in the case 110. A drivingrecorder is illustrated in FIG. 22 as an example, but the electronicdevice 100 is not limited to a driving recorder.

As shown in FIG. 22, the image module 120 includes the optical imaginglens set 1 as described above. FIG. 22 illustrates the aforementionedfirst example of the optical imaging lens set 1. In addition, theportable electronic device 100 also contains a barrel 130 for theinstallation of the optical imaging lens set 1, a module housing unit140 for the installation of the barrel 130, a substrate 172 for theinstallation of the module housing unit 140 and an image sensor 72disposed at the substrate 172, and at the image side 3 of the opticalimaging lens set 1. The image sensor 72 in the optical imaging lens set1 may be an electronic photosensitive element, such as a charge coupleddevice or a complementary metal oxide semiconductor element. The imageplane 71 forms at the image sensor 72.

The image sensor 72 used here is a product of chip on board (COB)package rather than a product of the conventional chip scale package(CSP) so it is directly attached to the substrate 172, and protectiveglass is not needed in front of the image sensor 72 in the opticalimaging lens set 1, but the present invention is not limited to this.

To be noticed in particular, the optional filter 70 may be omitted inother examples although the optional filter 70 is present in thisexample. The case 110, the barrel 130, and/or the module housing unit140 may be a single element or consist of a plurality of elements, butthe present invention is not limited to this.

Each one of the six lens elements 10, 20, 30, 40, 50 and 60 withrefractive power is installed in the barrel 130 with air gaps disposedbetween two adjacent lens elements in an exemplary way. The modulehousing unit 140 has a lens element housing 141, and an image sensorhousing 146 installed between the lens element housing 141 and the imagesensor 72. However in other examples, the image sensor housing 146 isoptional. The barrel 130 is installed coaxially along with the lenselement housing 141 along the axis I-I′, and the barrel 130 is providedinside of the lens element housing 141.

Please also refer to FIG. 23 for another application of theaforementioned optical imaging lens set 1 in a portable electronicdevice 200 in the second preferred example. The main differences betweenthe portable electronic device 200 in the second preferred example andthe portable electronic device 100 in the first preferred example are:the lens element housing 141 has a first seat element 142, a second seatelement 143, a coil 144 and a magnetic component 145. The first seatelement 142 is for the installation of the barrel 130, exteriorlyattached to the barrel 130 and disposed along the axis I-I′. The secondseat element 143 is disposed along the axis I-I′ and surrounds theexterior of the first seat element 142. The coil 144 is provided betweenthe outside of the first seat element 142 and the inside of the secondseat element 143. The magnetic component 145 is disposed between theoutside of the coil 144 and the inside of the second seat element 143.

The first seat element 142 may pull the barrel 130 and the opticalimaging lens set 1 which is disposed inside of the barrel 130 to movealong the axis I-I′, namely the optical axis 4 in FIG. 6. The imagesensor housing 146 is attached to the second seat element 143. Thefilter 70, such as an infrared filter, is installed at the image sensorhousing 146. Other details of the portable electronic device 200 in thesecond preferred example are similar to those of the portable electronicdevice 100 in the first preferred example so they are not elaboratedagain.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens set, from an object sidetoward an image side in order along an optical axis comprising: anaperture stop, a first lens element, a second lens element, a third lenselement, a fourth lens element, a fifth lens element and a sixth lenselement, said first lens element to said sixth lens element each havingan object-side surface facing toward the object side as well as animage-side surface facing toward the image side, wherein: said firstlens element has refractive power, and at least one of its object-sidesurface as well as its image-side surface is aspheric; said second lenselement has refractive power, an image-side surface with a concaveportion in a vicinity of its periphery and at least one of itsobject-side surface as well as its image-side surface is aspheric; saidthird lens element has an object-side surface with a concave portion ina vicinity of its periphery and an image-side surface with a convexportion in a vicinity of the optical axis; said fourth lens element hasan image-side surface with a convex portion in a vicinity of the opticalaxis and at least one of its object-side surface as well as itsimage-side surface is aspheric; said fifth lens element has positiverefractive power, an object-side surface with a convex portion in avicinity of the optical axis, and both its object-side surface and itsimage-side surface are aspheric; and said sixth lens element has anobject-side surface with a convex portion in a vicinity of the opticalaxis and a convex portion in a vicinity of its periphery, and both itsobject-side surface and its image-side surface are aspheric, the opticalimaging lens set exclusively has six lens elements, the first lenselement has a first lens element thickness T₁, the second lens elementhas a second lens element thickness T₂, the third lens element has athird lens element thickness T₃, the fourth lens element has a fourthlens element thickness T₄, the sixth lens element has a sixth lenselement thickness T₆ to satisfy (T₁+T₂+T₃+T₄)/T₆≦4.0.
 2. The opticalimaging lens set of claim 1, (T₃+T₆)/T₁≦1.9.
 3. The optical imaging lensset of claim 1, wherein the fifth lens element has a fifth lens elementthickness T₅ to satisfy (T₃+T₆)/T₅≦2.1.
 4. The optical imaging lens setof claim 1, wherein an air gap G₁₂ between said first lens element andsaid second lens element along said optical axis satisfies(T₃+T₆)/G₁₂≦8.0.
 5. The optical imaging lens set of claim 1, wherein anair gap G₃₄ between said third lens element and said fourth lens elementalong said optical axis satisfies (T₃+T₆)/G₃₄≦2.8.
 6. The opticalimaging lens set of claim 1, wherein an air gap G₅₆ between said fifthlens element and said sixth lens element along said optical axissatisfies (T₃+T₆)/G₅₆≦3.3.
 7. The optical imaging lens set of claim 1,wherein an air gap G₁₂ between said first lens element and said secondlens element along said optical axis and an air gap G₂₃ between saidsecond lens element and said third lens element along said optical axissatisfy (T₃+T₆)/(G₁₂+G₂₃)≦1.8.
 8. The optical imaging lens set of claim1, wherein an air gap G₂₃ between said second lens element and saidthird lens element along said optical axis and an air gap G₅₆ betweensaid fifth lens element and said sixth lens element along said opticalaxis satisfy (T₃+T₆)/(G₂₃+G₅₆)≦1.4.
 9. The optical imaging lens set ofclaim 1, (T₃+T₆)/T₂≦3.8.
 10. The optical imaging lens set of claim 1,wherein an air gap G₁₂ between said first lens element and said secondlens element along said optical axis satisfies (T₄+T₆)/G₁₂≦5.5.
 11. Anoptical imaging lens set, from an object side toward an image side inorder along an optical axis comprising: an aperture stop, a first lenselement, a second lens element, a third lens element, a fourth lenselement, a fifth lens element and a sixth lens element, said first lenselement to said sixth lens element each having an object-side surfacefacing toward the object side as well as an image-side surface facingtoward the image side, wherein: said first lens element has refractivepower, and at least one of its object-side surface as well as itsimage-side surface is aspheric; said second lens element has refractivepower, an image-side surface with a concave portion in a vicinity of itsperiphery and at least one of its object-side surface as well as itsimage-side surface is aspheric; said third lens element has anobject-side surface with a concave portion in a vicinity of itsperiphery and an image-side surface with a convex portion in a vicinityof the optical axis; said fourth lens element has an image-side surfacewith a convex portion in a vicinity of the optical axis and at least oneof its object-side surface as well as its image-side surface isaspheric; said fifth lens element has positive refractive power, anobject-side surface with a convex portion in a vicinity of the opticalaxis, an image-side surface with a concave portion in a vicinity of theoptical axis and both its object-side surface and its image-side surfaceare aspheric; and said sixth lens element has an object-side surfacewith a convex portion in a vicinity of its periphery, and both itsobject-side surface and its image-side surface are aspheric, the opticalimaging lens set exclusively has six lens elements, the first lenselement has a first lens element thickness T₁, the second lens elementhas a second lens element thickness T₂, the third lens element has athird lens element thickness T₃, the fourth lens element has a fourthlens element thickness T₄, the sixth lens element has a sixth lenselement thickness T₆ to satisfy (T₁+T₂+T₃+T₄)/T₆≦4.0.
 12. The opticalimaging lens set of claim 11, (T₃+T₆)/T₁≦1.9.
 13. The optical imaginglens set of claim 11, wherein the fifth lens element has a fifth lenselement thickness T₅ to satisfy (T₃+T₆)/T₅≦2.1.
 14. The optical imaginglens set of claim 11, wherein an air gap G₂₃ between said second lenselement and said third lens element along said optical axis satisfies(T₄+T₆)/G₂₃≦1.8.
 15. The optical imaging lens set of claim 11, whereinan air gap G₃₄ between said third lens element and said fourth lenselement along said optical axis satisfies (T₄+T₆)/G₃₄≦1.8.
 16. Theoptical imaging lens set of claim 11, wherein an air gap G₅₆ betweensaid fifth lens element and said sixth lens element along said opticalaxis satisfies (T₄+T₆)/G₅₆≦2.5.
 17. The optical imaging lens set ofclaim 11, wherein an air gap G₁₂ between said first lens element andsaid second lens element along said optical axis satisfies T₃/G₁₂≦2.9.18. The optical imaging lens set of claim 11, wherein an air gap G₁₂between said first lens element and said second lens element along saidoptical axis satisfies T₄/G₁₂≦2.6.
 19. The optical imaging lens set ofclaim 1, wherein an air gap G₁₂ between said first lens element and saidsecond lens element along said optical axis and the fifth lens elementwith a fifth lens element thickness T₅ satisfy T₅/G₁₂≦3.6.
 20. Theoptical imaging lens set of claim 1, wherein an air gap G₁₂ between saidfirst lens element and said second lens element along said optical axissatisfies T₆/G₁₂≦2.7.